The cars need to have a #clutch. The reason is that the #engine stays rotating while the wheels are stop at the same time ,
Thus there is no need to turn off the engine when you need to stop the wheels from moving. In addition, the
mechanism
Cam
A #cam is a rotating or sliding piece in a mechanical #linkage used especially in transforming rotary motion into linear motion or vice versa. It is often a part of a rotating wheel (e.g. an eccentric wheel) or shaft (e.g. a cylinder with an irregular shape) that strikes a lever at one or more points on its circular path
A cam #mechanism